Parachute Size

Problem Scenario

Broad Question

i am interested in parachutes

Specific Question

does the parachute size effect the parachutes rate of descent.

Hypothesis

the larger parachute will take longer to desend. the smaller parachute will desend faster.

Graph of Hypothesis

Variables

Independent Variable:plastic bags

Dependent Variable:rate of desent

Variables That Need To Be Controlled:

Shape of parachute

Vocabulary List That Needs Explanation

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General Plan

the general plan is too test whether the small,medium or large parachute will go fastest. the parachutes will all be dropped from the same height and timed all at the same time. there will be 3 parachutes and 3 timers. which ever parachute hits the ground first is the fastest parachute and which ever parachute hits last is the slowest. if all of the parachutes hit at the same time then the parachute size does not effect the parachutes rate of desent.

Potential Problems And Solutions

during the expirement the wind could be a problem and it would be a problem because the wind might slow one down or speed one up so i am not doing the expirement out side.

Safety Or Environmental Concerns

i will not use that much weight to pull the parachutes down that way it does not hit anyone.

Experimental Design

What is your experimental unit?

one parachute

Number Of Trials:

5

Number Of Subjects In Each trial:

3

Number of Observations:

15

When data will be collected

2\26\13 during science class

Where will data be collected?:

court yard at school

Resources and Budget Table

Item	Number needed	Where I will get this	Cost
plastic bags	3	home	na
string	16	home	na
paper cups	3	home	na
timers	1	home	na

Detailed Procedure

1. get all the materials for procedure
2. build 3 different parachutes and 3 different sizes small,medium and large
3. you will tie 4 strings off of each different sized bag
4. at the end of the dangling strings tie the 4 strings to a cup and then fill the cup up with paper clips to give it a little weight and pull it down
5. once you have all the parachutes ready you will drop them all at the same height but you will drop them at all different times
6. you will use the 1 timer to time how long each individual parachute will take to hit the ground
7. which ever one has the fastest time is the fastest parachute
8. if they all hit at the same time

Diagram

Photo List

parachutes

Time Line

experiment done by 2\26\13 Data Analysis done by 3\7\13 discussion and background done by 3\15\13 poster done by 3\22\13

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Data Table

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Data Analysis

All Raw Data

on my project i predicted that the small parachute would go the fastest and the large parachute would go the slowest at the end of the experiment i learned that the large parachute was the fastest and the small parachute was the slowest. The average rate of descent in seconds for the small parachutes is 2.514 and the average for the large parachute is 1.758

Graphs

Photos

Results

On my project I predicted that the the small parachute would go fastest and the large parachute would go slowest.My prediction was wrong.The large parachute went fastest with an average descent rate of 1.758. The small parachute went slowest at a descent rate of 2.154. The medium parachute was right in the middle of the two at a descent rate of 2.14.
Conclusion
My specific question was does the parachute size effect the parachute rate of descent. The size did effect the rate of descent. The smallest parachute went slowest at a descent rate of 2.154, the medium parachute descended at a rate of 2.14,and the large parachute went at a descent rate of 1.758. The differences between the fastest and the slowest is 0.404.

Discussion

Does the parachute size effect the parachute rate of descent.I predicted that the small parachute would go fastest,the large parachute would go slowest,and the medium size parachute would be right in the middle of the two. First I took 3 different size parachutes a small,medium,and large.I dropped all the different size parachutes 5 times each.I timed the parachutes every time i dropped them. I took the 5 times for every parachute and averaged them out.

For the small parachute i got an average of 2.154. For the medium size parachute I got an average of 2.14. For the large parachute i got an average of 1.758.My prediction was wrong,but I did figure out that the parachute size does effect the parachutes rate of descent.Knowing that the size of the shot does effect the descent velocity,this could help people in the army that jump out of planes with parachutes.

Benefit to Community and/or Science

knowing the size of the shot can effect the descent velocity this could help people who are in the army who have to jump out of planes with parachutes.

Background Research

Parachute Size As a general rule of thumb, design the 'chute so the descent velocity falls with in 3.5 to 4.5 meters per second (11.5 to 14.8 feet per second). You can determine the area of the parachute from the following equation: a round canopy. If you are using a canopy of another shape you can easily find the area from the following formula valid for regular polygons: where S is the area of the parachute, g is the acceleration due to gravity; which has a value of 9.81 m/s2 at sea level, m is the mass as measured in grams, r is the density of air (1225g/m3) at sea level, Cd is the coefficient of drag; estimated at 0.75 for a round canopy, and V is the descent velocity you choose. If you want a round canopy, the diameter is found by the formula: Fig. 2 Area for Round Parachutes


A parachute is a device used to slow the motion of an object through an atmosphere by creating drag, or in the case of ram-air parachutes, aerodynamic lift. Parachutes are usually made out of light, strong cloth, originally silk, now most commonly nylon. Parachutes must slow an object's terminal vertical speed by a minimum 75% in order to be classified as such. Depending on the situation, parachutes are used with a variety of loads, including people, food, equipment, space capsules, and bombs.

References

http://www.apogeerockets.com/downloads/Newsletter149.pdf

http://en.wikipedia.org/wiki/Parachute

Abstract

I wanted to figure how size effects the descent rate of a parachute falling. I dropped 3 different size parachutes with the same size string and same weight off a 15 foot ledge. I dropped each parachute 5 times each. There was a small,medium,and large parachute. I hypothesized that the small parachute would go fastest and the large parachute would go slowest. My hypothesis was completely opposite.